The mechanism of the biosynthesis of NGF will be studied by attempting to isolate native proNGF in order to see if only the gamma-subunit, the specific arginine esteropeptidase associated with NGF in the 7S NGF complex, will carry out the processing reaction. The development of a cell-free synthesis system to translate NGF mRNA will enable the capacity of cells and tissues other than the mouse submaxillary gland to synthesize NGF to be determined. NGF is internalized by sympathetic and PC12 cells and in the latter transported intact to the nucleus. In order to determine the significance of this process both its time course and its dependency on the external NGF concentration will be determined. Pulse chase experiments will also be used to define the critical time periods in this process and subcellular fraction to determine the precise pathway. DNA and RNA metabolism will also be measured as a function of NGF accumulation in the nucleus.